Abstract 17003: Impact of Ex-Vivo Lung Perfusion on T Regulatory Cells and Monocytes in Bronchoalveolar Lavage and Peripheral Blood

• DOI: 10.1161/circ.138.suppl_1.17003
• Publication Date: 2024-04-23T13:41:58Z
• Authors: Lourdes I Chacon; Gabriel T Loor; Daoud T Daoud; Ahmed T Alnajar; Luiz C Sampaio; Doris A Taylor

Background: Availability of donor lungs suitable for transplant falls short of current demand and results in long waiting times. More than 80% of donor lungs are potentially injured and therefore not considered suitable for transplantation. Ex-Vivo Lung Perfusion (EVLP) offers the opportunity to objectively assess and recondition organs unsuitable for immediate transplant. However, the biological mechanisms of EVLP are not well understood. The objective of this study was to investigate the Bronchoalveolar Lavage (BAL) and peripheral blood (PB) inflammatory cell profile in patients who had EVLP. We hypothesized that EVLP is related to a differential expression of monocytes in BAL and PB as compared to patients who did not receive EVLP.

Methods: BAL was collected and analyzed via flow cytometry at baseline (before transplant) and 6 h after transplant. PB was collected and analyzed at baseline, 6 h, 24 h, 48 h, and 72 h after transplant from consented participants (EVLP and non-EVLP, n=5 each). Statistical difference between groups were determined using t-test and nonparametric tests. A p-value <0.05 was considered significant.

Results: In the donor lung prior to transplant, classical monocytes (CD14+CD16-) were significantly higher in BAL at baseline (77.48±4.64 vs. 32.30±23.12, p=0.04) in the EVLP group when compared to non-EVLP group. In the recipients at 6 h after transplant, the EVLP group had a significant increase in T regulatory cells (Treg) (CD4+CD25+CD127dim) in BAL (4.08±1.2 vs. 18.00±6.61, p=0.05) and classical monocytes (CD14+CD16-) in PB (66.2 vs. 90.8, p=0.04) when compared to baseline. Additionally, the EVLP group had significantly higher M2 monocytes (CD14+CD80-CD163+) (86.97±7.21 vs. 62.85±3.15, p=0.03) in PB at 6 h after transplant when compared to non-EVLP group.

Conclusion: EVLP causes a significant change in monocytes, their subpopulations and regulatory T cells in the donor and recipient.